Are There One or More Geophysical Coupling Mechanisms before Earthquakes? The Case Study of Lushan (China) 2013
Several possible lithosphere–atmosphere–ionosphere coupling mechanisms before earthquake occurrence are presented in the literature. They are described by several models with different interaction channels (e.g., electromagnetic, mechanics, chemical, thermal), sometimes in conflict with each other....
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MDPI AG
2023-03-01
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| Online Access: | https://www.mdpi.com/2072-4292/15/6/1521 |
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| author | Yiqun Zhang Ting Wang Wenqi Chen Kaiguang Zhu Dedalo Marchetti Yuqi Cheng Mengxuan Fan Siyu Wang Jiami Wen Donghua Zhang Hanshuo Zhang |
| author_facet | Yiqun Zhang Ting Wang Wenqi Chen Kaiguang Zhu Dedalo Marchetti Yuqi Cheng Mengxuan Fan Siyu Wang Jiami Wen Donghua Zhang Hanshuo Zhang |
| author_sort | Yiqun Zhang |
| collection | DOAJ |
| description | Several possible lithosphere–atmosphere–ionosphere coupling mechanisms before earthquake occurrence are presented in the literature. They are described by several models with different interaction channels (e.g., electromagnetic, mechanics, chemical, thermal), sometimes in conflict with each other. In this paper, we search for anomalies six months before the Lushan (China) 2013 earthquake in the three geo-layers looking for a possible view of the couplings and testing if one or another is more reliable to describe the observations. The Lushan earthquake occurred in China’s Sichuan province on 20 April 2013, with a magnitude of Mw = 6.7. Despite the moderate magnitude of the event, it caused concern because its source was localized on the southwest side of the same fault that produced the catastrophic Wenchuan event in 2008. This paper applies a geophysical multi-layer approach to search for possible pre-earthquake anomalies in the lithosphere, atmosphere, and ionosphere. In detail, six main increases in the accumulated seismic stress were depicted. Anomalous geomagnetic pulsations were recorded in the Chengdu observatory, sometimes following the increased stress. Atmosphere status and composition were found to be anomalous in several periods before the earthquake, and, spatially, the anomalies seem to appear firstly far from the upcoming earthquakes and later approaching the Longmenshan fault where the Lushan earthquakes nucleated. The Formosat-3 data identified interesting anomalies in the altitude or electron content of the ionospheric F2 peak in correspondence with seismic and atmospheric anomalies 130 days before the earthquake. In addition, the total electron content showed high anomalous values from 12 to 6 days before the earthquake. We compared the anomalies and tried to explain their correspondences in different geo-layers by the lithosphere–atmosphere–ionosphere coupling models. In particular, we identified three possible couplings with different mechanisms: a first, about 130 days before the earthquake, with a fast (order of one day) propagation delay; a second, about 40 days before the earthquake occurrence, with a propagation delay of few days and a third from 2.5 weeks until one week before the event. Such evidence suggests that the geo-layers could interact with different channels (pure electromagnetic or a chain of physical-chemical processes) with specific propagation delays. Such results support the understanding of the preparation for medium and large earthquakes globally, which is necessary (although not sufficient) knowledge in order to mitigate their impact on human life. |
| first_indexed | 2024-03-11T05:58:33Z |
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| id | doaj.art-ae78433c595a40098192a86b7d2a7df0 |
| institution | Directory Open Access Journal |
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| spelling | doaj.art-ae78433c595a40098192a86b7d2a7df02023-11-17T13:38:15ZengMDPI AGRemote Sensing2072-42922023-03-01156152110.3390/rs15061521Are There One or More Geophysical Coupling Mechanisms before Earthquakes? The Case Study of Lushan (China) 2013Yiqun Zhang0Ting Wang1Wenqi Chen2Kaiguang Zhu3Dedalo Marchetti4Yuqi Cheng5Mengxuan Fan6Siyu Wang7Jiami Wen8Donghua Zhang9Hanshuo Zhang10College of Instrumentation and Electrical Engineering, Jilin University, Changchun 130061, ChinaCollege of Instrumentation and Electrical Engineering, Jilin University, Changchun 130061, ChinaCollege of Instrumentation and Electrical Engineering, Jilin University, Changchun 130061, ChinaCollege of Instrumentation and Electrical Engineering, Jilin University, Changchun 130061, ChinaCollege of Instrumentation and Electrical Engineering, Jilin University, Changchun 130061, ChinaCollege of Instrumentation and Electrical Engineering, Jilin University, Changchun 130061, ChinaCollege of Instrumentation and Electrical Engineering, Jilin University, Changchun 130061, ChinaCollege of Instrumentation and Electrical Engineering, Jilin University, Changchun 130061, ChinaCollege of Instrumentation and Electrical Engineering, Jilin University, Changchun 130061, ChinaCollege of Instrumentation and Electrical Engineering, Jilin University, Changchun 130061, ChinaCollege of Instrumentation and Electrical Engineering, Jilin University, Changchun 130061, ChinaSeveral possible lithosphere–atmosphere–ionosphere coupling mechanisms before earthquake occurrence are presented in the literature. They are described by several models with different interaction channels (e.g., electromagnetic, mechanics, chemical, thermal), sometimes in conflict with each other. In this paper, we search for anomalies six months before the Lushan (China) 2013 earthquake in the three geo-layers looking for a possible view of the couplings and testing if one or another is more reliable to describe the observations. The Lushan earthquake occurred in China’s Sichuan province on 20 April 2013, with a magnitude of Mw = 6.7. Despite the moderate magnitude of the event, it caused concern because its source was localized on the southwest side of the same fault that produced the catastrophic Wenchuan event in 2008. This paper applies a geophysical multi-layer approach to search for possible pre-earthquake anomalies in the lithosphere, atmosphere, and ionosphere. In detail, six main increases in the accumulated seismic stress were depicted. Anomalous geomagnetic pulsations were recorded in the Chengdu observatory, sometimes following the increased stress. Atmosphere status and composition were found to be anomalous in several periods before the earthquake, and, spatially, the anomalies seem to appear firstly far from the upcoming earthquakes and later approaching the Longmenshan fault where the Lushan earthquakes nucleated. The Formosat-3 data identified interesting anomalies in the altitude or electron content of the ionospheric F2 peak in correspondence with seismic and atmospheric anomalies 130 days before the earthquake. In addition, the total electron content showed high anomalous values from 12 to 6 days before the earthquake. We compared the anomalies and tried to explain their correspondences in different geo-layers by the lithosphere–atmosphere–ionosphere coupling models. In particular, we identified three possible couplings with different mechanisms: a first, about 130 days before the earthquake, with a fast (order of one day) propagation delay; a second, about 40 days before the earthquake occurrence, with a propagation delay of few days and a third from 2.5 weeks until one week before the event. Such evidence suggests that the geo-layers could interact with different channels (pure electromagnetic or a chain of physical-chemical processes) with specific propagation delays. Such results support the understanding of the preparation for medium and large earthquakes globally, which is necessary (although not sufficient) knowledge in order to mitigate their impact on human life.https://www.mdpi.com/2072-4292/15/6/15212013 Lushan earthquakemulti-layer studypre-earthquake anomalieslithosphereatmosphereionosphere |
| spellingShingle | Yiqun Zhang Ting Wang Wenqi Chen Kaiguang Zhu Dedalo Marchetti Yuqi Cheng Mengxuan Fan Siyu Wang Jiami Wen Donghua Zhang Hanshuo Zhang Are There One or More Geophysical Coupling Mechanisms before Earthquakes? The Case Study of Lushan (China) 2013 Remote Sensing 2013 Lushan earthquake multi-layer study pre-earthquake anomalies lithosphere atmosphere ionosphere |
| title | Are There One or More Geophysical Coupling Mechanisms before Earthquakes? The Case Study of Lushan (China) 2013 |
| title_full | Are There One or More Geophysical Coupling Mechanisms before Earthquakes? The Case Study of Lushan (China) 2013 |
| title_fullStr | Are There One or More Geophysical Coupling Mechanisms before Earthquakes? The Case Study of Lushan (China) 2013 |
| title_full_unstemmed | Are There One or More Geophysical Coupling Mechanisms before Earthquakes? The Case Study of Lushan (China) 2013 |
| title_short | Are There One or More Geophysical Coupling Mechanisms before Earthquakes? The Case Study of Lushan (China) 2013 |
| title_sort | are there one or more geophysical coupling mechanisms before earthquakes the case study of lushan china 2013 |
| topic | 2013 Lushan earthquake multi-layer study pre-earthquake anomalies lithosphere atmosphere ionosphere |
| url | https://www.mdpi.com/2072-4292/15/6/1521 |
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